Improved mode of treating vegetable substances for making paper-pulp



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' B NJ MIN c,- TmeHMaN; 0F rH-iaiDELPHu; PENNSYLVANIA. Letters No.'f'l0,485, datcd'lquvembcr 5, antgdutedLOctober 26,1867.

moon or mime VEGETABLE amnesia flamers-Penman jut? 5tl1thl1lt roan-ii intiate your; fi itcutiuh'matiug omit the time. I c

Be it known that I, Bsn'nnmi Cnsvr TrLo'nMAN, of Philadelphia,Pennsylvania, have invented new and useful Improuemcntsin'Treating-Vegetable Substances, and obtaining products therefromapplicableto the tion thereof. 7

My invention consists in ofsu'lphurous' acid in m, lieuteilinter-cellular incrustin for other. uses, aecordin I have found that ttends to-make the fibrous product of a Thevfollowing is; a method ofpoplar mod to be use The whitest parts-of thewoo inn and I declare thefollowing to be a full-descripo-proee'ss of treating t egetable-substances which contain fibres with asolution close vcssel u'ndenapressure sufiieient to retain'tho acid gas untilthc g or cementing "inalter existing betireen the'fibrcs dissolved, either partiallyer wholly;as may be desired, andaiibro'us pr'oduict'is obtained suitable forthe'manufrictur of paper-pulp, or of fibres; or

d fer paper-pulp.

g to the nature ofthe materiel employed; o I v 1 he additional sul'phitcor bisulphiteof lime, or other suitable base, to the acid solutionwhiter color, and more easily bleached; y carrying my-iuvontion intoeil'ect 'teking for example the case of hen sleek or (l are to beselected to rnaliey'rhite papennnd it is to be cut across the grain intoslices about one-eighth to one-quarter of 'an inch long; A strongirenysscl, of any convenient size and shapqlinedyith lead, and providedwith esteem-jacket, and with the necessary pipes, cocks, and man-holesfor filling and emptying the ch pressure, and temperature,

ofabout specific grav ity.1.025 to 1.6315,

raise its dcnsity to about specific gravity 1.0.l toil-085s then run inuntil the vessel is nearly full, allowing for the'absorption of theliquid by the fieodandits expansion by heat, sothat the wood may he keptconstantly 607-,

cred by the liquid during the operation. I I I jacket until theteuiphratur v at which it is l'gept daring about six to eighthod'rsf;

urge, and ivith gauges, safety-wolves, and'thernimncters, to is aboutt'wo-thi'rds filled withthe slicedwood.

indicate-height of lie aid, ,Asolution of salphurous acid in water,- iliars has been dissolved, suliicient'to 1 in which 'a quantity ofsulphite 'o,

' Theye'sscl is then closed, and heat is applied by ineans of the steameof the liquid is about to'oihundred, and sixty degrees Fahrenheit, (260Fahrenhcit,)

The steam is tlien shut oil front the steals-jacket and fresh water isforced into the top of thevessci, thefacid solution being at the seinetime allowed to escape gradually from belowf into a-coyered lead-line dtuh,-where'=it ishoilcd'b'y steam until the sulphurous acid gas is.expelled.

- ;This 'gas is conveyed by a pipe to a suitable condenser, :n'hcre' itis absorbed by cold n'ater, to he reused-on another charge of need. Aquantity rnay bet-eased. Instead 0 ou, the acid may he neutra "Aftei'being'washed, the woody s of sulphitelof"lixne will generally-bedeposited during the boilingj which i driving ed the sulphu'rousacid'gds by boiling, or after partof it has'vbeeu thus driven lize dbythe'a dditio n oi hydrate of lime, forrning sulphite of lime, whichcan be reused. ubstanco is left to draijman lithen, ifpn examina'tioa itis thought necessary in ordcr to, complete the separation andbleaching)? the-fibrcgitiis to be again-treated rvith afresh charge ofsulphurousacid and sul bite at a'tol'nperature or. abouftuo hundredand'sixty to-two hundred and eighty 7 degrees-Fahrenheit (260 to 2 8 0Fahrenliei t) during about three to five hours} Then the acid liquid isto be run oil as before, and the fibrous product iswashed'uutil'all theacid'and soluhle'matters m extracted. 'It 'isthen" taken out of thelead-liued vessel snd beutcnginlopnlp by the ordinary machines.-

- e m e he fi lm sflk; 1 I a 1 r v sper, Iprefer that thetrestr'uentshould be'i'epeated as often is necessity when makingp'ulpfor ordinary-p I fa -solubl has been extracted fromjthe'uood; solesto'leav'e the fibres withjrcsh 'acid,solu tions, until evoryth If notsuia'ciently white, it

clean, and separable into pulp by aisligl t inechaniealirubhing'. Manykinds of vegetable: fibrous substances I are considerably bleached-bytifcatinente fIhewhiterwat-ieties of ;some uoods, hickory and'hemlockfer 1 ceincntingmattor app then rcducing thcse iotofincr tablefibrous substance, trc'ate ears to be gradual and progressiy, firstloosening the substance into coarse fibres, and and'stillfinerconstituents, until perfect pulpis produced; d so ssfto dissolve .its'cementing matter only partially, will be found capable of Wood or otherVega being reduced by ineehanical' beating'and rubbing to a mass offibres, or: sort of coarse pulp, applicable to uses Y .fn herc strengthand s The solvent'action of the hot acid liquid I through the pores ofthe 51, such as wrapping -paper, pastcboard,nxilhhoard papicr-mache,Ste. on the wood may heniade more rapid causing it to circulate freelyby any .of the usual znethodgeithsr mechanical, suoh as pumps,1stirrers,or agita- 4 I I tors, or by causing a column of the liquid to bemore'highly heated than the rest, so as to rise-t0 the top andditi'usejitself, or, where the scale of mnnuiactu'reis sufiicientlylarge, by havin'gseve ral vessels filled with the materials, throughwhich the hot ucidliquid is forcedto pass in succession, so that freshacid, solution is applied to wood clLeudynearly-exhaust od of solublematter, and the nearly saturated acid solution is brought into contactwith fresh'wood. {These arrangements are, familiar to chemicalengincers,.'and need not be. further described.

When-making papc r-pulp of cone, bamboo, or' palmetto, or of esparto orother grasses, oroti straw, roads or other annual plants, the operatiomis performed asialready described, and they are generally more rapidlyacted on than wood. Cotton, linen, and -henr'pen'rags, ropes, Ste -maybe advantageously treated in this manner, and'will be rendered more easyto reduce into pulp by the usual mechanical means. I l

I prefer with allkinds of materials to operate atas'low a temperatureand with as weaklacid solutions as is compatible with a practicalrapidity of working. I l y i when flax, hemp, or other long-tibredplants are to be treated to obtain fibres t er spinning, I opern t c inthe manner-above described, but to avoid too much disintegration andweakening of tho fibre, care must be taken to graduate the extent of theaction according to the nature oi' the material usedand the effectdesired to be produced. I p H i The dissolving action of the acidsolution appears to talte ellect first upon the matter cementing thelong compound fibres to each other and to the stem of the plant, andnext attacks the ccmontingmatter of the long compound fibresthemsclves',reducing them into a number of shorter and finer fibres. Ifthe action instill longer continued, these are still furtherdisintegrated, and. beeonie atlasflso short and fine as to be unfit forspinning and suitable for paper-pulp. It, on the other hand, thedissolving action is not carried far enough, the long fibres do notseparate readily from each other and from the stem and skin of theplant. The attention of tba operator must therefore be given to arrestthoaction atthe .precisopoint most suitablet'or the object he has inview, whether a fibrous strong as possible, even, though somewhat lessfine and less easy 'toclea'n, ora finer and cleaner fibre,but somewhatshorter and weakerf- Different kinds of plants, and of diilercntdegreesot' maturity, require different degreesof action offthe solventliquid inorder to produce a given result; I thercforetollow the progressof the operation, and ascertain when the desired degree ofdisintegration is obtained b'y'taking samples from tiino to timebymcannof a rod ending in noel-Escrow, and working through etailing. box' andstopcock in the sidcof-thc vessel, as is well understood by engineers. p

In order to render Ithc'operatioh morci-graduxil, I prefer. to workrat-comparatively low temperatures, say

about ta'ohundredto two hundred and "twenty degrees Fahrenheit, (200 to220 Fahrenheit and with veryweak solutions of 'su'lphurous acid ofnboutspeciiic gravity 11002 to 1.004, to which is added a quantity 'ofsulphite oflime, suilicient to raise its density to about 1.005 to 1.008specific gravity.

Un'de'r' these conditions I have obtained anlcdiuui degree of looseningand separation of tho-fibre of flax in about four hours; It is desirablethat plants of nearly uniform size and growth should be selected tojbeoperated on together, and they are to be left of their natural length,and not cut, as in the case of wood, for paper-pulp. When about totreats, new material, I prefer to ascertain by preliminary trials onsmall quantities tholen'gtli of time and degree of action best adaptedto the object desired, u'hichean afterwards be adhered to. p

When the treatment is'finished thc acid and soluble matters are to bethoroughly washed out, and tho fibres are to be manufactured in theusual manner. V

Straw, grasses, osiers, young woods, and similar vegetable fibroussubstances treated in this manner, sons to dissolve only partially thecementing matter of their fibres, will become more flexible andmorcsuitable for making hats, mats, baskets, and hoops, andiforotheruseswhere-pliahility is required. a r

'I do not confine inyselt' to the kind of apparatus above-described,which forms no part of my invention, or

:t o the particular mode of working detailed, as my invention can'bocarried into ellcet innny convenient method and apparatus by whieh'thesubst ancii which contains the fibre can bedigostcd. in a hot solutionof sulph'urous acid, in a close vessel, under pressure, so as toprevcn'ttho oscape'of the acid gas. Many forms of apparatus are incommon use, r have been described and published, forwashing-andblcachingfibrous substances, -und.'for

making paper-pulp, by boiling or digesting 'rags, 'wood, ntraw,'&c., in-hot alkaline and other solutions, which l can readily be adapted .toworking my invention'by chemical'en'gineers. I

The volatility of the acid, and its corrosive action on metals, must beprovided for, and the inside of the apparatus should be lined with leador other, suitable material. 1 I

The vessels used when operating with the acid solutions and,temperatures aboyc described for treating wood for paper-pulp, should beof about tlie strength'usuallyallowed for steam-boilers working'at apressure of one hundred pounds per squaro inch.

I have stated the density of acid solution,:thc dogrecot' heat, and thelength ot' time which I prefer-in practice, but I do not confinem yseltthercto,as these conditions may be greatly: varied, and may to someextent be' substituted for each other. i s a I l a v The stronger theacid solution the more rapid is the uction at a given temperature. Also,the higher the temperature the more rapid is the action with agivoodensity of acid solution. With-weak a'cid and compare-r tively lowtemperature, the eflect can be produced by continuing the. digestion asuficiently. long time. Qr'by using nsolution saturated when cold withacid' gas at or above common atmospheric pressure, the action may bemade more rapid.

Care must be tnken,-l1owcver, that the temperature be not raised-highenough to cause a blackening action on the vegetable substance, which isapt to take place with some materials at about three hundred degreesFahrenheit, (300 Fahrenheit) and more readily in the treatment with thefirst charge of acid than with the succeeding ones.

I consider it more prudent to work the first charge .on wood at not overtwo hundred and sixty degrees Fahrenheit, (260 Fahrenheit,) and thesubsequent charges at not over two hundred and eighty degreesFahrenheit, (280 Fahrenheit.)

I have foundthat in the second and subsequent doses of acid solution ona charge of wood, a smaller proportion of sulphite may be used than inthe first dose.

Where the first extraction has very nearly exhausted the soluble matter,I have sometimes used-solution of sulphurous acid alone, without anysulphiteforthe subsequent doses. The solution of sulphurous acid inwater at the requisite temperature appears to be the etfieient agent indissolving the intercellular 'or cementingmatter of the vegetablefibrous substance, and where the c olor of the product is of noconsequence, the operation may be performed with the sulphurous acidsolution alone, without the addition of sulphite.' In this case areddish brown color is given to the resulting fibrous product, and theacid solution will be found to contain a quantity of free sulphuricacid, whichhas been formed during the operation by the oxidation of aportion of the sulphurous acid. The presence of a sulphito in the acidsolution prevents thisreddening client, and in case of many substances aconsiderable bleaching of the fibrous product takes place.

The probable mode of action of the sulphite is to present-a base withwhich the sulphuric acid combines as-v soon as it is formed, and is thusprevented from further action.

There are other classes of salts which operate to some extent in thesame way as the sulphites, but are] less cheap and convenient. Therequisites are, first, that'tho salt should not be capable of beingdecomposed by thesolution of sulphurons acid at the temperature andpressure employed; second, that it should be ca able I of beingdecomposed by a weak solution of sulphuric acid at the temperature andpressure employed; third,

that the acid thus set free should not have the property of coloringthe-fibre at the temperature and pressure employed. 1 v

v Many of the salts of the weaker acids (aoetatcsfor example) wouldfulfill these conditions to a considerable extent, but asthey are moreexpensive'than the sulphites, there is no inducement to use them.

Besides its cheapness, the sulphite of liuie has the advantage offurnishing anfequivalent of snlphurous acid when decomposed by thesulphuric acid, and is also very readily recoverable from the spent acidsolutions.

I prefer to use a quantity of sulphite of lime, suil'icient to insurethat some 0t the salt shall be present in the acidsolution during thewhole operation, and that some shall remain undecomposed after theaction on the fibrous substance is completed. 7

I have sometimes used solutions of sulphurous acid saturated withsulphite, and sometimes have used $111.

phite in powder mixed amongtbe wood, &c., operated upon. After thesulphurous-ac'id has been driven oil or precipitated, the liquid extractcontaining in a soluble form the products of the saline andjntercellularor." cementing constituents of the plants may be utilized in variousways in the arts, ormay be used as manure. It contains a weak organicacid, somewhat resembling ulmic acid, and when boiled down has someot'the properties of gum.

What I claim as myinvention, and desire to secure by LettersPatent, is-

The process of treating vegetable substances which contain fibres with asolution of sulphurous acid in water,

either with or without the addition of sulphites, or other salts ofequivalent chemical properties, as above explained, heated in a closevessel under pressure to a temperature sufiicient to cause it todissolve the intcrccllular incrdst ing or cementing constituents of.said vegetable substances, so as to leave the undissolved product inafibrous state, suitnble for the manufacture of paper, paper-pulp,cellulose. or fibres, or for other purposes, aocordin g to the nature ofthe material employed. I

I also claim as new articles o manufacture, the two products obtained bytreating vegetable substances which contain fibres with a solution ofsnlphurons acid in water,.either with or without the addition ofsulphitcs or other salts of equivalent chemical properties, as -aboveexplained, heated in a close vessel. under pressure'to a temperaturesuflicient to cause it to dissolve the intercellnlar or incrustingconstituents of said vegetable substances, one of saidproducts beingsoluble in water, and containing the elements of .the starchy, gummy, d

.saline constituents of the plants, andthe other product being aninsoluble fibroiis material applicable to-the manufacture of paper,paper-pulp, cellulose, or fibres,-or to other purposes, according to thenature of the material employed.

I also claim the use and application, in the manufacture of paper,paper-pulp, cellulose, and fibres, of the fibrous material produced bytreating vegetable substances which contain fibres with a solution ofsulphurous acid in water, either with or without the addition ofsulphites, or ether salts of equivalent chemical properties, as aboveexplained, heated in a close vessel under pressure to a temperaturesufiicient to cause it to dissolve the incrirsting or inter-cellularconstituents of said vegetable substances. 1 v

I also 'claim the-use and application of sulphites or other salts' ofequivalent chemical properties, as above explained,- in combinationwith'a solution of sulphurous acid in water, as an agent in treatingvegetable substances which contain fibres, when heated therewith in .aclose vessel under pressure to a temperature 'suificicnt to cause saidacid solution to dissolve the intercellular or incrusting constituentsof said-vegetable substances. I also claim the recovery and rense'ofsulphurous acid andsulphite from the acid liquids which have beendigested on the vegetablefihrous substances, by boiling said liquids, orneutralizing them with hydrate of lime.-

i B. C. 'JPI-LGHMAN.- Witnesses: I I

Anna 'Trnemuu,

Mum- T mqmm

